UserAgent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/28.0.1500.95 Safari/537.36
Example URL:
All existing html pages
Steps to reproduce the problem:
1. Create element div in simple html page with css fixed dimensions and black border,
example of box: <div style="width:300pt; height:300pt; border:1pt solid black;"></div>
2. press Ctrl+p, choose you printer and Print page directly to the printer or save as PDF
3. After printing HTML page on paper determine printed box dimensions and compare size with defined in html page.
or if you printed page as PDF file thereafter Print this PDF as printed paper.
What is the expected behavior?
HTML element lengths in the printed paper page or PDF page should be have same as defined in the size of element.
Also in printed PDF, tested boxes should be have same dimensions.
If box has defined as 105.83mm x 105.83mm in HTML page, when also expected printed box dimensions 105.83mm x 105.83mm
What went wrong?
Printed element box sizes in the paper page is really greater and not corresponds with the defined sizes of element in the HTML page.
Also printed PDF has wrong dimensions.
Defined box sizes in HTML page has 105.83mm x 105.83mm but printed box dimensions are round 113mm x 113mm.
Does it occur on multiple sites: Yes
Is it a problem with a plugin? No
Did this work before? N/A
Does this work in other browsers? Yes FF v23.0 and IE 10.0.8
Chrome version: 28.0.1500.95 Channel: stable
OS Version: 6.1 (Windows 7, Windows Server 2008 R2)
Flash Version: Shockwave Flash 11.8 r800
Attached HTML file for testing and resulted PDF file.
Unfortunately I cannot attach also the printed paper ;)
Of course You can reproduce this issue also in all other length Units : mm, pt, inch, em etc.

Very simple test is to create a div, set width: 50mm, height: 50mm and print it. Will print at ~53mm on both height and width. Same issue, with the same scaling problem with cm.
Tested on Ubuntu 14.04,
OS X
Consistent on both platforms.
As with previous comment Chrome bloats mm calculations and is always incorrect. Firefox prints the correct dimensions.
All boxes in the attachment should print at 5cm, all print at 5.3cm.

It's seems to be because Chrome scales the html. Add a div 100% width to the page and the size will be corrected. Furthermore, add 200% width div and the html will be scaled smaller. http://stackoverflow.com/questions/14223843/print-exact-measurements-in-chrome/25245512#25245512

This seems to be a workaround in some cases -> http://stackoverflow.com/a/28132441 ...
In one case I had to use another workaround, where I downscaled the whole HTML via CSS3 transforms by a ratio of ~0.94 to receive the correct print dimensions on paper ...
All very ugly and non future proof hacks. An upstream fix is highly appreciated.